Punch press

ABSTRACT

For perforating a workpiece, a press with a two-way fluid operated actuator which is mounted on a support and is operable to reciprocate a punch through a hole in the support into and out of the workpiece. The actuator comprises a cylinder, a cap, a piston, and a ram with a ram guide formed integrally with the cylinder, and the cap and the cylinder are joined together and mounted on the support by studs which are threaded on the opposite end portions. To distribute both the stretching due to the tightening stress on the studs more uniformly over the entire length of the studs, each stud is formed with a center portion of reduced diameter, this diameter being no greater than the root diameter of the threaded end portions. The studs extend through fastener holes in the cap, the cylinder, and the support. So that these holes can be drilled in the separate pieces and then be easily aligned when the press is assembled and mounted on the support, guide holes of equal diameter are formed in the cap, the cylinder, and the support thus allowing the same template to be used to drill the fastener holes in each piece around the guide hole in that piece.

[72] Inventors Harry Conn;

Robert W. Mauk; Paul M. Lancaster, all of Rockford, Ill.

211 App]. No. 881,026 [22] Filed Dec. 1, 1969 [45] Patented Oct. 19, 1971 [73] Assignee W. A. Whitney Rockford, Ill.

[54] PUNCH PRESS 8 Claims, 2 Drawing Figs.

[52] U.S. Cl 83/639, 83/698 [51] 1nt.Cl 826d 5/12 [50] Field of Search 83/639, 698; 72/453; 100/269 R, 269 B [56] References Cited UNITED STATES PATENTS 796,523 8/1905 Morse 83/639 X 865,857 9/1907 Bond..... 83/639 X 2,215,643 9/1940 Gorham 83/639 X 3,449,993 6/1969 Temple et al 83/639 3,469,487 9/1969 Brolund 83/639 X 3,478,678 11/1969 Lickliter et al. 83/639 X Primary Examiner-Frank T. Yost Attorney-Wolfe, Hubbard, Leydig, Voit & Osann ABSTRACT: For perforating a workpiece, a press with a twoway fluid operated actuator which is mounted on a support and is operable to reciprocate a punch through a hole in the support into and out of the workpiece. The actuator comprises a cylinder, a cap, a piston, and a ram with a ram guide formed integrally with the cylinder, and the cap and the cylinder are joined together and mounted on the support by studs which are threaded on the opposite end portions. To distribute both the stretching due to the tightening stress on the studs more uniformly over the entire length of the studs, each stud is formed with a center portion of reduced diameter, this diameter being no greater than the root diameter of the threaded end portions. The studs extend through fastener holes in the cap, the cylinder, and the support. So that these holes can be drilled in the separate pieces and then be easily aligned when the press is assembled and mounted on the support, guide holes of equal diameter are formed in the cap, the cylinder, and the support thus allowing the same template to be used to drill the fastener holes in each piece around the guide hole in that piece.

PUNCH PRESS BACKGROUND OF THE INVENTION This invention relates to a press with a reciprocating punch for perforating a workpiece and, more particularly, to a press of the type in which the punch is connected to and reciprocated by the ram of a fluid operated actuator with a piston slidable back and forth in the chamber of a cylinder in response to the admission of pressure fluid alternately into opposite ends of the chamber and with a cap closing one end of the cylinder. The actuator is mounted on the upper surface of a support over a generally upright hole in the support with the punch slidably telescoped therein and with the ram being guided in a ram guide, the actuator being connected to the support by studs threaded on opposite end portions. The studs extend through fastenerholes in the actuator and the support and are threadably engaged at the opposite same template portions to hold the actuator on the support.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a self-contained actuator which may be removed from one support and mounted on another support without having to align the ram in another ram guide and which can be assembled and mounted on the support with less likelihood of the connections of the cap to the cylinder and the actuator to the support becoming loose during operation than has been true of similar presses therefore known.

It is more detailed object to accomplish the above by fonning the ram guide as a part of the cylinder and by using the same set of studs not only to mount the actuator on the support but also to join the cap to the cylinder.

It is an important object of the present invention to provide studs which during assembly and mounting of the actuator will stretch to a greater extent than studs used heretofore in similar devices to maintain the studs tightly threadably engaged through repeated active strokes of the actuator thus keeping the actuator tightly assembled and mounted on the support.

It is a related object to accomplish the above by forming the studs with a center portion of reduce diameter not greater than the root diameter of the threaded end portions to insure a more uniform stretching of each stud through the length of the stud.

It is a further object to insure ease of alignment of the fastener holes during the assembly of the actuator and the mounting of the latter on the support by forming the cap with a central depression and by the diameters of the depression, the chamber, and the upper end portion of the upright hole being equal so that the same template can be used in drilling the fastener holes in each piece.

The invention also resides in the provision of a novel flange formed around the cap and telescoped over the cylinder to deflect any pressure fluid which might spew from the chamber during the active stroke of the actuator.

Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS FIG. I is a cross-sectional view of a machine embodying the novel features of the present invention.

FIG. 2 is an enlarged, fragmentary cross section taken substantially along the line 2-2 in FIG. 1 with the center portions of the cross section removed for purposes of clarity.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in the drawings for purposes of illustration, the invention is embodied in a portable press (FIG. 1) having a fluid operated actuator 11 supported on a C-shaped frame or support 12 and operable to reciprocate a movable tool element 13 through advance and return strokes relative to a fixed tool element 14 on the support and cooperating with the movable tool element to perform a machining operation on a workpiece 15 such as a piece of sheet metal disposed between the two elements. Herein, the fixed tool element is a female die supported on a lower arm 16 of the support and vertically aligned with the movable tool element which is a punch adapted to telescope downwardly into the die and punch out holes in the workpiece on the downstroke of the actuator. The press is suspended from a grapple 17 (FIG. 1) of an overhead crane (not shown) and may be moved to various positions within the work area to operate on difierent workpieces or on different portions of the same workpiece.

As shown most clearly in FIG. 1, the actuator l l is mounted upright on an upper arm 18 of the support 12 and comprises a cylinder 19 with a central chamber 20 in which a piston 21 is slidable up and down in response to the admission of pressure fluid, in this instance oil, alternately into opposite ends of the chamber through conduits 22 and 23 communicating with a suitable pressure source for supplying oil to the chamber at a pressure of approximately 5,000 psi. A cap 24 extends across the the upper end of the cylinder, and a plug 25 depending from the cap is telescoped into the upper end portion of the chamber to close the upper end of the chamber. In this instance, an O-ring 26 (FIG. 2) encircles the plug and bears against the wall of the chamber to retard the leakage of oil during the downward or active stroke of the actuator. Anchored to the piston and slidably telescoped in a ram guide 27 is a ram 28 to which the punch 13 is connected, the ram and the punch being telescoped into an upright hole 29 formed in the upper arm 18. To attach the punch to the ram, the punch is telescoped loosely into a coupling nut 30 (FIG. I) which is threaded at its upper end onto a cylindrical neck 31 formed on the lower end of the ram. As the nut is tightened, mating tapers 32 on the nut and the punch engage one another to draw the upper end of the punch into tight abutment with the lower end of the neck. The usual stripper 34 (FIG. I) is threaded into the lower end portion of the hole 29 in the upper arm 18 to limit upward movement of the workpiece 15 on the return stroke of the punch.

In accordance with one aspect of the invention, the ram guide 27 is formed as an integral part of the cylinder 19 and is telescoped into the upright hole 29, and only one set of fasteners, in this instance studs 35, are utilized to assemble the actuator and mount the latter on the upper ann I8 of the support 12, the studs extending through the cap 24, the cylinder, and into the upper arm. With this arrangement, the actuator 11 can easily be assembled and mounted on the support or removed from one support and mounted on another support and, during initial assembly of the actuator, the ram 28 is aligned in the ram guide thus resulting in no further alignment of the ram in the ram guide being necessary if the actuator is removed from one support and mounted on another support. Further, by using a single set of studs, there is no need to tighten one set of studs to hold the cylinder together and then tension another set of studs to hold the cylinder on the support. As a result, loosening of the various parts under the ram force is reduced.

To mount the actuator 11 on the upper surface of the upper arm 18 of the support 12, the studs 35 extend through generally vertical fastener holes 36 (FIG. 2) in the cap 24, the cylinder 19 and the upper support arm 18 to hold the cap on the cylinder and join the two to the upper support am. As shown in FIG. 2, the studs are elongated rods threaded on the opposite end portions 37 and 38. Each fastener hole in the upper support arm is threaded with the lower end portion 38 of each stud being threaded into one of the threaded holes. A washer 39a is telescoped over and a nut 39 is threaded onto the upper end portion 37 of each stud, the upper end portions projecting above the cap. In this instance, there are 15 studs, and the actuator is capable of exerting tons of pressure on the punch I3 thus resulting each stud being subjected to 10 tons of stress during the power stroke of the actuator. More force must be used to tighten the nuts and stress the studs between the nuts and the upper support arm than is imposed on the studs during the active stroke of the actuator or the studs will loosen thus allowing the cap and cylinder to become loosely joined together and loosely mounted on the upper support arm. Additionally, the stress of the tightening force on the studs is so great that the washers slowly sink into or become embedded in cap.

in accordance with another aspect of the present invention, the studs 35 are formed to allow greater overall stretching during initial tightening of the nuts 39 than has been true of studs used in similar presses heretofore thus maintaining the actuator ll tightly assembled and mounted on the support 12 even if the washers 39a should become embedded in the cap 24 or the nuts should work loose. For this purpose, each stud is formed with a center portion 40 (FIG. 2) of reduced diameter which is equal to or less than the root diameter of the threaded end portions of the stud. With this arrangement, the center portion of each stud will stretch per unit of length an amount equal to or greater than an equal unit of length of the threaded end portions thus allowing greater overall stretching of each stud while reducing the possibility that the threaded end portions will stretch beyond acceptable limits before the required tightening stress is reached. Moreover, even though each stud contracts if its washer should become embedded in the cap, that stud remains partially stretched to continue to exert a force tending to hold the actuator 11 tightly assembled and mounted.

In this instance, each nut 39 is tightened to such an extent that the tension force exerted on each stud 35 is much greater than the tons needed to hold the actuator 11 tightly assembled during the power stroke of the actuator. With the tension force being exerted on the nuts 39 and washers 39a tending to pull the washers toward the cap 24 and with the force exerted during the power stroke of the actuator 11 tending to move the cap toward the washers, the washers sometimes slowly become embedded in the cap thus allowing the stretched studs to contract slowly. As each stud contracts, the tensional force in the stud reduces. With each stud being stretched a greater amount than has been possible heretofore, the stud can contract through a greater distance while still being tensioned between the support arm 18 and the nut, the tension reducing as the stud contracts. Because during initial assembly, the studs are tensioned an amount greater than that necessary to withstand the power stroke of the actuator, the slow embedding of the washers which might occur with the resulting contraction of the studs does not quickly reduce the total stress on each stud below 10 tons thus resulting in the actuator being tightly assembled and securely mounted on the support 12 for a longer service life than has been true previously.

To insure accurate and easy alignment of the fastener holes 36 in the cap 24 and the cylinder 19 during the assembly of the actuator 11 and the alignment of these fastener holes with the fastener holes in the upper support arm 18 during the mounting of the actuator on the upper support arm. The cap, the cylinder, and the arm advantageously are formed so that a single template (not shown) may be used to drill all of the fastener holes. For this purpose, three parts are formed with central holes of the same diameter. As shown in FIG. 1, the cap is formed with a central hole or depression 42 in the upper surface of the cap, and the diameters of the chamber 20 of the cylinder and the upper end portion 43 (FIG. 2) of the upright hole 29 in the upper support arm are equal and equal to the diameter of the depression. The same template thus can be used to drill all the fastener holes 36 to insure alignment of the fastener holes during assembly.

Advantageously, the cap 24 is formed to prevent oil from hitting any person standing near the press 10 should the oil spew out of the chamber 20 due to failure of the O-ring 26 during a power stroke of the actuator 11. With the high pressure in the upper end of the chamber during a power stroke, the O-ring can fail and thus allow some of the oil from the chamber to spew out horizontally between the top of the cylinder 19 and the bottom surface of the cap. To deflect any such spewing oil downwardly thus protecting anyone near the press, a depending annular flange 45 (FIG. 2) is formed around the periphery of the bottom surface of the cap.

It will be observed that fonning the ram guide 27 as a part of the cylinder 19 and using only one set of studs 35 both to join the cap 24 to the cylinder and to mount the actuator 11 on the support 12 is a particularly beneficial arrangement. ln this way, the necessity for aligning the ram in the ram guide each time the actuator is removed from one support and mounted on another support is eliminated, and the use of a single set of studs provides an overall assembly which is less likely to loosen under the force of the power stroke. A particularly advantageous arrangement is the formation of each stud with a center portion 40 of reduced diameter which is no greater than the root diameter of the threaded end portions 37 and 38 so that the stretching of the stud due to stress on the stud from tightening during assembly is distributed along the length of the stud rather than being concentrated in the threaded end portions. With this arrangement, the stretching of the threaded end portions can be kept within acceptable limits during assembly while allowing greater overall stretching for easy assembly and less likelihood of loosening of the stud as a result of the power stroke of the actuator should the washers 39a become embedded in the cap 24. Also of advantage is the formation of holes of equal diameter in the cap, the cylinder, and the upper support arm 18 so that the same template can be used to drill all the fastener holes thus insuring easy alignment of these holes during the assembly of the actuator and the mounting of the latter on the upper support arm.

We claim as our invention:

1. In a press for perforating a workpiece, the combination of, a support having an upright hole formed therethrough, a punch slidably telescoped in said hole, a fluid operated actuator for reciprocating the punch mounted on the upper surface of said support, said actuator comprising a cylinder with a central chamber having a piston slidable back and forth in said chamber in response to admission of pressure fluid alternately into opposite ends of said chamber, a cap mounted on the upper end of said cylinder to close said chamber and having a central depression formed in its upper surface, a downwardly extending flange formed around said cap and telescoped over said cylinder to deflect downwardly any pressure fluid which might spew from said chamber during the active stroke of said actuator, a ram guide depending from said cylinder and telescoped into said hole, a ram connected at one end to said punch and at the opposite end to said piston and slidably telescope'd into said ram guide, a plurality of generally vertical fastener holes formed through said cap, through said cylinder, and in said support, the diameters of the upper end portion of the first said hole, said chamber, and said depression being equal so that a single template can be used in drilling said fastener holes to insure alignment of the fastener holes from the cap to support, a plurality of fasteners positioned in said fastener holes, each fastener comprising a stud threaded on opposite end portions, and means threaded onto each said threaded end portion for holding each stud stressed between said cap and said support to join said cap and said cylinder together and mount the actuator on said support, each said stud being formed with a center portion of reduced diameter not greater than the root diameter of the threaded end portions to allow the center portion of each stud to stretch during mounting of the actuator on the support thus distributing stretching due to tension stress more evenly along the length of the stud for easier mounting of the actuator on the support and less likelihood of the fasteners being loosened as a result of the power stroke of the actuator.

2. In a press for perforating a workpiece, the combination of, a support having an upright hole formed therethrough, a punch slidably telescoped in said hole, a fluid operated actuator for reciprocating the punch mounted on the upper surface of said support, said actuator comprising a cylinder, a piston slidable back and forth in said cylinder in response to admission of pressure fluid alternately into opposite ends of said cylinder, a cap mounted on the upper end of said cylinder to close said cylinder, a ram guide depending from said cylinder and telescoped into said hole, a ram connected at one end to said punch and at the opposite end to said piston and slidably telescoped into said ram guide, a plurality of generally vertical fastener holes fon'ned through said cap, through said cylinder, and in said support, a plurality of fasteners positioned in said fastener holes and each fastener comprising, a stud threaded on opposite end portions, means threaded onto each said threaded end portion for holding each stud stressed between said cap and said support to join said cap and said cylinder together and to said support, and each said stud being formed with a center portion of reduced diameter which is not greater than the root diameter of the threaded end portions to allow the center portion of each stud to stretch during the mounting of the actuator on the support thus distributing stretching due to tension stress more evenly along the length of the stud for easier mounting of the actuator on the support and less likelihood of the fasteners being loosened as a result of the power stroke of the actuator.

3. The press of claim 2 in which a downwardly extending flange is formed around said cap and telescoped over said cylinder to deflect downwardly any pressure fluid which might spew from said cylinder during the active stroke of said actuator.

4. The press of claim 2 in which said piston is slidable within a central chamber formed within said cylinder, the upper surface of said cap is formed with a central depression, and the diameters of the upper end portion of said upright hole, said chamber, and said depression are equal so that a single template can be used in drilling said fastener holes to insure easy alignment of the fastener holes from the cap to the support.

5. In a press for perforating a workpiece, the combination of, a support having an upright hole formed therethrough, a punch slidably telescoped in said hole, a fluid operated actuator for reciprocating said punch removably mounted on the upper surface of said support, said actuator comprising a cylinder having a piston slidable back and forth therein in response to the admission of pressure fluid alternately into opposite ends of said cylinder, a cap mounted on the upper end of said cylinder to close said cylinder, a ram guide rigid with and depending from said cylinder and telescoped into said hole, a ram connected at one end to said punch and at the opposite end to said piston and slidably telescoped into said ram guide, a plurality of generally vertical fastener holes formed through said cap, through said cylinder, and in said support, and a plurality of fasteners positioned in said fastener holes and tensioned between said cap and said support to sandwich said cylinder between said cap and said support and thus mount said actuator with said ram guide and said ram on said support as a single unit so that said actuator may be formed as a single unit with said ram guide and said ram to eliminate the necessity of aligning said ram with said ram guide during mounting of the actuator on said support.

6. The press of claim 5 in which a downwardly extending flange is formed around said cap and telescoped over said cylinder to deflect downwardly any pressure fluid which might spew from said cylinder during the active stroke of said actuator.

7. The press of claim 5 in which said piston is slidable within a central chamber formed within said cylinder, the upper surface of said cap is formed with a central depression, and the diameters of the upper end portion of said upright hole, said chamber, and said depression are equal so that a single template can be used in drilling said fastener holes to insure easy alignment of the fastener holes from the cap to the support.

8. The press of claim 5 in which each fastener comprises a stud threaded on opposite end portions and each stud is formed with a center portion of reduced diameter not greater than the root diameter of the threaded end portions to allow the center portion of each stud to stretch during mounting of the actuator on the support thus distributing stretching due to tension stress more evenly along the length of the stud. 

1. In a press for perforating a workpiece, the combination of, a support having an upright hole formed therethrough, a punch slidably telescoped in said hole, a fluid operated actuator for reciprocating the punch mounted on the upper surface of said support, said actuator comprising a cylinder with a central chamber having a piston slidable back and forth in said chamber in response to admission of pressure fluid alternately into opposite ends of said chamber, a cap mounted on the upper end of said cylinder to close said chamber and having a central depression formed in its upper surface, a downwardly extending flange formed around said cap and telescoped over said cylinder to deflect downwardly any pressure fluid which might spew from said chamber during the active stroke of said actuator, a ram guide depending from said cylinder and telescoped into said hole, a ram connected at one end to said punch and at the opposite end to said piston and slidably telescoped into said ram guide, a plurality of generally vertical fastener holes formed through said cap, through said cylinder, and in said support, the diameters of the upper end portion of the first said hole, said chamber, and said depression being equal so that a single template can be used in drilling said fastener holes to insure alignment of the fastener holes from the cap to support, a plurality of fasteners positioned in said fastener holes, each fastener comprising a stud threaded on opposite end portions, and means threaded onto each said threaded end portion for holding each stud stressed between said cap and said support to join said cap and said cylinder together and mount the actuator on said support, each said stud being formed with a center portion of reduced diameter not greater than the root diameter of the threaded end portions to allow the center portion of each stud to stretch during mounting of the actuator on the support thus distributing stretching due to tension stress more evenly along the length of the stud for easier mounting of the actuator on the support and less likelihood of the fasteners being loosened as a result of the power stroke of the actuator.
 2. In a press for perforating a workpiece, the combination of, a support having an upright hole formed therethrough, a punch slidably telescoped in said hole, a fluid operated actuator for reciprocating the punch mounted on the upper surface of said support, said actuator comprising a cylinder, a piston slidable back and forth in said cylinder in response to admission of pressure fluid alternately into opposite ends of said cylinder, a cap mounted on the upper end of said cylinder to close said cylinder, a ram guide depending from said cylinder and telescoped into said hole, a ram connected at one end to said punch and at the opposite end to said piston and slidably telescoped into said ram guide, a plurality of generally vertical fastener holes formed through said cap, through said cylinder, and in said support, a plurality of fasteners positioned in said fastener holes and each fastener comprising, a stud threaded on opposite end portions, means threaded onto each said threaded end portion for holding each stud stressed between said cap and said support to join said cap and said cylinder together and to said support, and each said stud being formed with a center portion of reduced diameter which is not greater than the root diameter of the threaded end portions to allow the center portion of each stud to stretch during the mounting of the actuator on the support thus distributing stretching due to tension stress more evenly along the length of the stud for easier mounting of the actuator on the support and less likelihood of the fasteners being loosened as a result of the power stroke of the actuator.
 3. The press of claim 2 in which a downwardly extending flange is formed around said cap and telescoped over said cylinder to deflect downwardly any pressure fluid which might spew from said cylinder during the active stroke of said actuator.
 4. The press of claim 2 in which said piston is slidable within a central chamber formed within said cylinder, the upper surface of said cap is formed with a central depression, and the diameters of the upper end portion of said upright hole, said chamber, and said depression are equal so that a single template can be used in drilling said fastener holes to insure easy alignment of the fastener holes from the cap to the support.
 5. In a press for perforating a workpiece, the combination of, a support having an upright hole formed therethrough, a punch slidably telescoped in said hole, a fluid operated actuator for reciprocating said punch removably mounted on the upper surface of said support, said actuator comprising a cylinder having a piston slidable back and forth therein in response to the admission of pressure fluid alternately into opposite ends of said cylinder, a cap mounted on the upper end of said cylinder to close said cylinder, a ram guide rigid with and depending from said cylinder and telescoped into said hole, a ram connected at one end to said punch and at the opposite end to said piston and slidably telescoped into said ram guide, a plurality of generally vertical fastener holes formed through said cap, through said cylinder, and in said support, and a plurality of fasteners positioned in said fastener holes and tensioned between said cap and said support to sandwich said cylinder between said cap and said support and thus mount said actuator with said ram guide and said ram on said support as a single unit so that said actuator may be formed as a single unit with said ram guide and said ram to eliminate the necessity of aligning said ram with said ram guide during mounting of the actuator on said support.
 6. The press of claim 5 in which a downwardly extending flange is formed around said cap and telescoped over said cylinder to deflect downwardly any pressure fluid which might spew from said cylinder during the active stroke of said actuator.
 7. The press of claim 5 in which said piston is slidable within a central chamber formed within said cylinder, the upper surface of said cap is formed with a central depression, and the diameters of the upper end portion of said upright hole, said chamber, and said depression are equal so that a single template can be used in drilling said fastener holes to insure easy alignment of the fastener holes from the cap to the support.
 8. The press of claim 5 in which each fastener comprises a stud threaded on opposite end portions and each stud is formed with a center portion of reduced diameter not greater than the root diameter of the threaded end portions to allow the center portion of each stud to stretch during mounting of the actuator on the support thus distributing stretching due to tension stress more evenly along the length of the stud. 